A common complaint among serious photographers is that their cameras don’t focus accurately. “Back-focus” and “front-focus” are both dreaded ailments that can plague any SLR (digital or film) and lens combination. Fresh from the factory, lens and camera are supposed to be calibrated so this doesn’t happen. However, not only does that not always occur, but once a lens and camera are in the field, it is only a matter of time before slight changes in the alignment can cause focus to drift.

Calibrating the autofocus? Do I really need it? Can I do it myself? The answer is yes to all of the above questions, but there are a few considerations to make, so let’s start from the beginning. Although we like to think our brand new camera and lenses are perfect out of the box, real life says it doesn’t always work that way. How many times while shooting a portrait, have we’ve focused on the eye, and the real sharper point was an eyelash or worst, the nose or the ear?

Now that we have seen in this article why we need to calibrate the autofocus of our camera/lens combination (CLC) let’s see how to do it. In a nut-shell, we point the camera at the SpyderLENSCAL, we focus on the vertical target, take a picture, and by zooming in the picture (on the camera display or, better, on a computer screen) we can verify on the ruler whether the front or rear section is sharper (ideally should be the zero, but….) In case the numbers in the ruler’s front area are sharper than zero, then the lens is ‘front focusing’, in case the numbers on the rear are sharper, then the lens is back focusing and we can use the in-camera menu to fine tune the focus. That’s the quick explanation, let’s go through the in depth process.

SpyderLENSCAL Auto-Focus Adjustment Test Shot[/caption]Here’s an update to the list of cameras capable of being fine-tuned by SpyderLENSCAL, including cameras released or announced at Photokina. The latest Canon models actually allow calibration at both ends of the zoom range of zoom lenses, making SpyderLENSCAL even more important.